1. Field of the Invention
This invention relates to subscriber loop carrier telephone systems and, more particularly, to remote power sources for operating the remote terminal of such systems.
2. Description of the Prior Art
It has been customary to operate telephone subscriber equipment from a central office battery. This arrangement renders telephone service independent of the availability of electrical power from other utilities. Unfortunately, this arrangement has several disadvantages when an attempt is made to power electronic circuits at the remote subscriber location.
A major problem in operating electronic circuits from a central telephone office battery is that such batteries are high voltage sources in order to provide adequate talking current over long telephone lines. Modern semiconductor electronic circuits, on the other hand, operate at much lower voltage levels. Simple voltage dropping devices consume power and thus are wasteful of available energy. Furthermore, the current drawn by such remote electronics causes a large voltage drop in the telephone loop making the operation of the talking circuits less reliable.